In the previous sections, we demonstrated what is the check-operator technique in the simplest example of matrix models. In the next two sections we illustrate it in a more involved example of two-dimensional conformal field theories [1]}, [2]}, [3]}, [4]}, [5]}. The conformal block in this theory is also described by a matrix model, however, being a function, not just a formal series has more tricky global behaviour. This is one of the avatars of the AGT correspondence [6]}, [7]}, [8]}, which implies that the conformal block can be described as a \(\beta \) -ensemble of the Dotsenko–Fateev type [9]}, [10]}, [11]}, [12]}, [13]}, [14]}, [15]}, [16]}, [17]}.
